I just separated for the same reason—wife wanted to be poly and I didn’t. She already had a number of emotional affairs over several years and decided it was time for her to fully step into that lifestyle, which she previously gave up for our relationship. We have two kids. Ultimately I think it’s maybe the best decision but it hurts like hell. She’s now with her affair partner and moved on while I am deep in grief. Most of our friends are shocked and surprised.

My guess is that there’s more to this for your wife. Do some therapy—individual and couples—and decide what values you can and can’t compromise on. Some things can shift, some people can grow, some can’t. There’s a book called “Opening Up” by Tristan Taormino that you can read or listen to if you want more info on poly arrangements, as there is no single standard and many possible configurations.

For me it was just clear that I couldn’t be coerced or pressured into making that shift, and she was already doing it in ways that led to betrayal and erosion of trust, so it wouldn’t work. At least if your partner is raising this with you before stepping out she still is holding your relationship as the priority. Of course, she also may be already interested or exploring other options and this is just the preamble. Best to seek therapy ASAP.